Thursday, May 22, 2008

It would be interesting to provide some methods for two-way communication in the aprs.fi web user interface. Say, APRS messaging from a sort of a web chat, as a simple and obvious example. Or marking their position on the web map and having it seen on APRS-IS. Having tracker devices with an open-source firmware (like OpenTracker and the Finnish HaMDR) opens up more interesting solutions, like remote control, or actively requesting information from a vehicle.

But how on earth could I figure out if an user of the web site is a licensed amateur radio operator, so that he can be allowed to transmit? Automatically, with somewhat strong authentication against an existing database or set of databases, without a need for validating each user by hand? To be useful, it would need to work for more than a few countries (Finland, USA to start with).

It's quite unlikely that the issuers of the licenses (like the FCC in the USA, Ficora in Finland) would bother to create Internet authentication services for their license databases. But the amateur leagues (at least ARRL in the USA, and SRAL in Finland) are already giving out accounts to their web sites ("for members only" features), and I suppose they also know whether each member is licensed or not.

What if the leagues would provide an authentication service using the OpenID protocol? An user would first type in their ARRL or SRAL email address (oh7foo@sral.fi, or n1example@arrl.org), then provide their sral.fi or arrl.org password to SRAL's or ARRL's site, and the authentication result, together with licensing status, would be passed back to aprs.fi (or another "licensed hams only" site).

This would require for the users to be members of one of the organizations providing OpenID authentication. But maybe some individual or organization could set up a trusted OpenID-enabled amateur database, charging each user $2 for the work of validating their license status.

Please, post a comment if you have any ideas for automatically validating the license status of a web site user.

Version 1.12 includes a parser for the !DAO! extension, which can be used in uncompressed and mic-e APRS packets to report the datum and an additional digit of position resolution. It also reports the position resolution (in meters) for parsed position packets, depending on the type of the packet (compressed, mic-e, uncompressed), the presence of DAO and the amount of position ambiguity. These improvements were implemented by Tapio, OH2KKU.

I felt an urge to do some slight improvements on it myself before releasing it, and couldn't come with anything that would be both quick to implement and actually useful, so I just added some tests, cleaned up the API and packaging slightly, fixed POD documentation style, upgraded MakeMaker, and added a little example script, just to make CPANTS happier and increase the Kwalitee rating a bit. :)

A few minutes ago I installed the new parser code on aprs.fi, so those of you transmitting uncompressed or mic-e packets with the DAO extension should now see the improved precision.

Compressed format packets have enough precision (around 1 foot) already, so DAO is not useful with it. aprs.fi properly decodes compressed packets (including speed and course), and compressed packets are the smallest ones (they help conserve valuable channel time on 144.39 and 144.800 MHz), so I would recommend using the compressed format instead of uncompressed or mic-e with DAO.

The only supported datum is still WGS84, no conversion from other datums specified by DAO is done.